Reduced pitch memory subsystem for memory device

ABSTRACT

A memory device includes an array of memory cells and a plurality of bit-lines with each bit-line connected to a respective set of memory cells of the array of memory cells. The memory device includes a memory subsystem having first and second memory circuits. Each first memory circuit can be disposed laterally adjacent to a second memory circuit. Each first memory circuit includes a first bit-line connection and each second memory circuit including a second bit-line connection, the first and second bit-line connections can connect to respective bit-lines. Each first bit-line connection is disposed on a first bit-line connection line of the memory subsystem and each second bit-line connection is disposed on a second bit-line connection line of the memory subsystem, and the second bit-line connection line can be offset from the first bit-line connection line by a predetermined distance that is greater than zero.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a division of U.S. patent application Ser. No.16/986,776, filed Aug. 6, 2020, which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to memory devices, and, inparticular, the present disclosure relates to reduced pitch memorysubsystems for memory devices.

BACKGROUND

Memory devices are typically provided as internal, semiconductor,integrated circuits in computers or other electronic devices. There aremany different types of memory including random-access memory (RAM),read only memory (ROM), dynamic random access memory (DRAM), synchronousdynamic random access memory (SDRAM), static random access memory(SRAM), and flash memory. As memory devices advance, it is desirable tomake memory devices, including memory subsystems, as small and/or asdense as possible.

For the reasons stated above, and for other reasons stated below whichwill become apparent to those skilled in the art upon reading andunderstanding the present specification, there is a need in the art formemory subsystems that allow for smaller pitches.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an embodiment of a memory systemin accordance with the present disclosure.

FIGS. 2A and 2B illustrate top plan views of simplified layout diagramsof protection circuits in accordance with the present disclosure.

FIGS. 3A to 3C illustrate top views of simplified block diagrams ofportions of protection circuits in accordance with the presentdisclosure.

FIG. 3D illustrates an alternate configuration for bit-line nodes andsource nodes in accordance with the present disclosure.

FIGS. 4A and 4B illustrate side and top views of an integrated planarNMOS-vertical PMOS inverter in accordance with the present disclosure.

FIGS. 5A and 5B illustrate side and top views of an integrated verticalCMOS inverter in accordance with the present disclosure.

FIGS. 6A to 6D illustrate top views of inverter interconnection that arein accordance with the present disclosure.

FIGS. 7A and 7B illustrate alternate embodiments for the interconnectionof FIG. 6D.

FIGS. 8A to 8C illustrate intermediate components formed in an exemplaryfabrication process for an integrated inverter in accordance with thepresent disclosure.

FIGS. 9A to 9G illustrate intermediate components formed in an exemplaryfabrication process for an integrated inverter in accordance with thepresent disclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown, byway of illustration, specific embodiments. In the drawings, likenumerals describe substantially similar components throughout theseveral views. Other embodiments may be utilized and structural,logical, and electrical changes may be made without departing from thescope of the present disclosure. The following detailed description is,therefore, not to be taken in a limiting sense.

The term “semiconductor” used herein can refer to, for example, a layerof material, a wafer, or a substrate, and includes any basesemiconductor structure. “Semiconductor” is to be understood asincluding silicon-on-sapphire (SOS) technology, silicon-on-insulator(SOI) technology, thin film transistor (TFT) technology, doped andundoped semiconductors, epitaxial layers of a silicon supported by abase semiconductor structure, as well as other semiconductor structureswell known to one skilled in the art. Furthermore, when reference ismade to a semiconductor in the following description, previous processsteps may have been utilized to form regions/junctions in the basesemiconductor structure, and the term semiconductor can include theunderlying layers containing such regions/junctions.

Some exemplary embodiments of the present disclosure can be directed toa memory device such as, for example, a flash memory device. Flashmemory devices (e.g., NAND, NOR, etc.) have developed into a popularsource of non-volatile memory for a wide range of electronicapplications. Non-volatile memory is memory that can retain its datavalues for some extended period without the application of power. Flashmemory devices typically use a one-transistor memory cell that allowsfor high memory densities, high reliability, and low power consumption.Changes in threshold voltage of the memory cells, through programming(which is sometimes referred to as writing) of charge-storage structures(e.g., floating gates or charge traps) or other physical phenomena(e.g., phase change or polarization), determine the data value of eachmemory cell. Common uses for flash memory and other non-volatile memorymay include personal computers, personal digital assistants (PDAs),digital cameras, digital media players, digital recorders, games,appliances, vehicles, wireless devices, mobile telephones, and removablememory modules, and the uses for non-volatile memory continue to expand.

In a NOR flash architecture, memory cells, arranged in a column, arecoupled in parallel, with each memory cell coupled to a data line, suchas a bit line. A “column” refers to a group of memory cells that arecommonly coupled to a local data line, such as a local bit line. It doesnot require any particular orientation or linear relationship, butinstead refers to the logical relationship between memory cell and dataline. Typically, the array of memory cells for NAND flash memory devicesis arranged such that the control gate of each memory cell of a row ofthe array is connected together to form an access line, such as a wordline. Columns of the array include strings (often termed NAND strings)of memory cells connected together in series, e.g., source to drain,between a pair of select lines, e.g., a source select line and a drainselect line. The source select line includes a source select gate ateach intersection between a NAND string and the source select line, andthe drain select line includes a drain select gate at each intersectionbetween a NAND string and the drain select line. Each source select gateis connected to a source line, while each drain select gate is connectedto a data line, such as column bit line.

The present disclosure is directed to a memory device having an array ofmemory cells. The memory device includes a plurality of bit-lines witheach bit-line connected to a respective set of memory cells of the arrayof memory cells. The memory device can include a memory subsystem havinga set of first memory circuits and a set of second memory circuits. Eachfirst memory circuit can be disposed laterally adjacent to a secondmemory circuit. Each first memory circuit includes a first bit-lineconnection and each second memory circuit including a second bit-lineconnection, the first and second bit-line connections can be adapted toconnect to respective bit-lines of the plurality of bit-lines. In someembodiments, each of the first bit-line connections is disposed on afirst bit-line connection line of the memory subsystem and each of thesecond bit-line connections is disposed on a second bit-line connectionline of the memory subsystem, and the second bit-line connection linecan be offset from the first bit-line connection line by a predetermineddistance that is greater than zero.

In another embodiment a memory device includes an array of memory cellsand a plurality of bit-lines with each bit-line connected to arespective set of memory cells of the array of memory cells. The memorydevice includes a memory circuit having a memory latch. The memory latchincludes a first integrated inverter having at least one verticaltransistor and a second integrated inverter having at least one verticaltransistor. In some embodiments, each integrated inverter includes acommon input gate that has a gate-all-around configuration.

FIG. 1 is a simplified block diagram of a NAND flash memory device 100in communication with a processor 130 as part of an electronic system,according to an embodiment. The processor 130 may be a memory controlleror other external host device. Memory device 100 includes an array ofmemory cells 104. A row decoder 108 and a column decoder 110 areprovided to decode address signals. Address signals are received anddecoded to access memory array 104.

Memory device 100 also includes input/output (I/O) control circuitry 112to manage input of commands, addresses, and data to the memory device100 as well as output of data and status information from the memorydevice 100. An address register 114 is in communication with I/O controlcircuitry 112, and row decoder 108 and column decoder 110, to latch theaddress signals prior to decoding. A command register 124 is incommunication with I/O control circuitry 112 and control logic 116 tolatch incoming commands. Control logic 116 controls access to the memoryarray 104 in response to the commands and generates status informationfor the external processor 130. The control logic 116 is incommunication with row decoder 108 and column decoder 110 to control therow decoder 108 and column decoder 110 in response to the addresses.

Control logic 116 is also in communication with memory subsystemcircuits that can include a cache register 118, a data register 120,and/or a circuit-protection subsystem 150. Cache register 118 latchesdata, either incoming or outgoing, as directed by control logic 116 totemporarily store data while the memory array 104 is busy writing orreading, respectively, other data. During a write operation, data ispassed from the cache register 118 to data register 120 for transfer tothe memory array 104; then new data is latched in the cache register 118from the I/O control circuitry 112. During a read operation, data ispassed from the cache register 118 to the I/O control circuitry 112 foroutput to the external processor 130; then new data is passed from thedata register 120 to the cache register 118. A status register 122 is incommunication with I/O control circuitry 112 and control logic 116 tolatch the status information for output to the processor 130.

A circuit-protection subsystem 150, according to various embodiments,can be arranged between data register 120 (and/or cache register 118)and memory array 104. For example, low-voltage circuitry of dataregister 120 and/or cache register 118 may be coupled to one side (e.g.,a low-voltage side) of the circuit-protection subsystem 150 and datalines or bit-lines of memory array 104 may be coupled to another side(e.g., a high-voltage side) of the circuit-protection subsystem 150.

Memory device 100 receives control signals at control logic 116 fromprocessor 130 over a control link 132. The control signals may includeat least a chip enable CE#, a command latch enable CLE, an address latchenable ALE, and a write enable WE#. Memory device 100 receives commandsignals (which represent commands), address signals (which representaddresses), and data signals (which represent data) from processor 130over a multiplexed input/output (I/O) bus 134 and outputs data toprocessor 130 over I/O bus 134.

For example, the commands are received over input/output (I/O) pins[7:0] of I/O bus 134 at I/O control circuitry 112 and are written intocommand register 124. The addresses are received over input/output (I/O)pins [7:0] of bus 134 at I/O control circuitry 112 and are written intoaddress register 114. The data are received over input/output (I/O) pins[7:0] for an 8-bit device or input/output (I/O) pins [15:0] for a 16-bitdevice at I/O at control circuitry 112 and are written into cacheregister 118. The data are subsequently written into data register 120for programming memory array 104. For another embodiment, cache register118 may be omitted, and the data are written directly into data register120. Data are also output over input/output (I/O) pins [7:0] for an8-bit device or input/output (I/O) pins [15:0] for a 16-bit device.

It will be appreciated by those skilled in the art that additionalcircuitry and signals can be provided, and that the memory device ofFIG. 1 has been simplified. It should be recognized that thefunctionality of the various block components described with referenceto FIG. 1 may not necessarily be segregated to distinct components orcomponent portions of an integrated circuit device. For example, asingle component or component portion of an integrated circuit devicecould be adapted to perform the functionality of more than one blockcomponent of FIG. 1 . Alternatively, one or more components or componentportions of an integrated circuit device could be combined to performthe functionality of a single block component of FIG. 1 .

Additionally, while specific I/O pins are described in accordance withpopular conventions for receipt and output of the various signals, it isnoted that other combinations or numbers of I/O pins may be used in thevarious embodiments. The configuration of memory array 104 is known tothose skilled in the art and thus will not be further discussed exceptas needed to describe the exemplary embodiments of the presentdisclosure. In addition, although the exemplary embodiments may bediscussed in conjunction with a NAND flash architecture, the embodimentsdescribed herein are not limited to NAND flash, and exemplaryembodiments can include other flash architectures, such as NOR flash,etc.

Data lines are sometimes coupled to circuitry that may be configured tohandle relatively low voltages (e.g., that may be referred to aslow-voltage circuitry), such as data cache circuitry. The low-voltagecircuitry may provide relatively low voltages (e.g., 0 V up to about 4V) to the data lines during read or write operations. However, duringerase operations (e.g., involving NAND memory arrays), memory cells maybe erased a block at a time by grounding all of the access lines in theblock, for example, while allowing the data lines to float. A relativelyhigh erase voltage (e.g., about 20 V to 30 V) is then applied to asemiconductor on which the memory cells are formed, and thus to thechannels of the memory cells, to remove the charge from thecharge-storage structures. This can cause the data lines to float toabout the erase voltage and can damage the low-voltage circuitry coupledto data lines.

Protection devices, such as field-effect transistors (FETs), may becoupled between the bit lines and low-voltage circuitry, such as, forexample, the low-voltage circuitry of data cache 118 and/or thelow-voltage circuitry of data register 120, to protect the low-voltagecircuitry from the relatively high voltages that may be present on thebit lines during an erase operation. For example, an FET may be turnedoff during an erase operation to protect the low-voltage circuitry fromthe relatively high voltages that may be present on the bit lines, andthe FET may be turned on during a read or write operation to pass therelatively low voltages between the low-voltage circuitry and the bitlines. Each circuit-protection device may be formed on an active regionthat is separated and electrically isolated from an adjacent activeregion, on which an adjacent circuit-protection device is formed, by anisolation region, such as a shallow-trench isolation (STI) region. A bitline may be coupled to a high-voltage side of a circuit-protectiondevice, and the low-voltage circuitry may be coupled to a low-voltageside of a circuit-protection device. For example, for an FET, a contact(e.g., that may be referred to as a high-voltage-side contact) cancouple a bit line to a source/drain region on the high-voltage side, anda contact (e.g., also referred to as a low-voltage-side contact) maycouple low-voltage circuitry to a source/drain region on the low-voltageside. The circuit-protection devices may be coupled on a one-to-onebasis to the bit lines or one circuit-protection device to two or moredata lines through a multiplexer. However, the pitch of thecircuit-protection devices may be relatively large (e.g., 38 nm orgreater) in order to avoid breakdown of the circuit-protection devices.The relatively large pitch uses up considerable area and thus mayincrease the size of the memory device.

FIGS. 2A and 2B are top plan views of an exemplary embodiment of aportion of circuit-protection subsystem 150 that can include a pluralityof protection circuits 210 to provide high-voltage isolation (e.g.,isolating a 20V to 30V signal). Similar protection circuits arediscussed in detail in Applicant's U.S. Pat. Nos. 8,766,365 and10,163,893, which are incorporated herein by reference in their entiretyas background. Accordingly, for brevity, description of the protectioncircuits herein focuses on the features of the present inventivetechnology. In addition, although exemplary embodiments of the presentdisclosure are provided using circuit-protection devices associated withthe cache and/or data registers, those skilled in the art willunderstand that the present disclosure is applicable to other types ofmemory circuits such as, for example, circuits that connect to othertypes of data lines.

In exemplary embodiments of the present disclosure, thecircuit-protection subsystem 150 can include a set of one or moreprotection circuits 210 arranged in a line 212 (e.g., verticallyarranged as shown in FIG. 2A) and another set of one or more protectioncircuits 210 arranged in a line 214 of protection circuits 210.Representative protection circuits 210 are identified by dottedrectangles. Each protection circuit 210 can include a source/drain node220, a polysilicon gate 215 (also referred to herein as data gate 215),and a source/drain node 222. The node 220 (also referred to herein aslow-voltage (LV) node 220) can be coupled to low-voltage circuitry suchas data cache 118 and/or data register 120 via, for example, contact 225(“LV contact 225”). Depending on the memory operation (e.g., erase,read, program, etc.), the node 222 can be coupled to circuitry that canhave a relatively high voltage (e.g., about 20V to about 30V during,e.g., erase operation) and/or a relatively low voltage (e.g., about 0Vto about 4V during, e.g., read or program operations). In someembodiments, each node 222 (also referred to herein as bit-line (BL)node 222) can be connected to a respective bit line of the memory array104 via, for example, contact 227 (“BL contact 227”). In operation, thedata gates 215 can be turned on to connect LV nodes 220 to BL nodes 222when low-voltage memory operations, such as, for example, read/programoperations, are taking place. When high-voltage memory operations, suchas, for example, erase operations, are taking place, the data gates 215can be turned off to isolate the LV nodes from the high-voltage on theBL nodes 222. As used herein, a BL node and corresponding BL contact canalso be referred to herein as BL connection.

Portions of the protection circuits 210 can be respectively formed inindividual active regions 228 that are defined by isolation regions 230,e.g., STI regions, formed in the semiconductor. Each active region 228can include the respective LV node 220, the data gate 215, and canextend to the corresponding BL node 222 surrounding the BL contact 227(see, e.g., arrows 228 in FIG. 2A). The isolation regions 230 can beformed on either side of one or more active regions 228. Each isolationregion 230 electrically isolates and/or physically separates adjacentactive regions 228 from each other. The semiconductor may be comprisedof silicon, e.g., monocrystalline silicon, and, for example, may beconductively doped to have a conductivity type, e.g., a p-typeconductivity, e.g., to form a p-well.

In some embodiments, the circuit-protection subsystem 150 can include anactive area 232 that is configured to form one or more transistors, suchas, for example, FETs. The active area 232 can be covered by apolysilicon layer that forms a common gate 235 for the one or moretransistors that can, in some embodiments, extend beyond the activeregion 232. In some embodiments, the polysilicon layer can be segmentedsuch that more than one gate (e.g., gates similar to common gate 235)are formed. In some embodiments, the active region 232 can include oneor more source (SRC) nodes 237 that can be formed in openings in thepolysilicon layer. The SRC nodes 237 can include contacts 239 that canbe connected to a voltage source. As used herein, an SRC node andcorresponding SRC contact can also be referred to herein as a SRCconnection. In some embodiments, the active area 232 can include atleast a portion of the BL nodes 222. The one or more transistors definedby the common gate 235 can be configured such that, when the common gate235 is on, the BL nodes 222 and the one or more SRC nodes 237 areconnected and, when the common gate 235 is off, the BL nodes 222 and theone or more source nodes 237 are isolated from each other. In someembodiments, unlike the LV nodes 220, the BL nodes 222 and/or the SRCnodes 237 are not separated from each other by isolation regions (e.g.,STI) formed in the semiconductor. Instead, the BL nodes 222 areselectively and electrically coupled to each other and to the one ormore SRC nodes 237 by the common gate 235. In some embodiments, activeregions 228 can be contiguous with active region 232. That is, activeregions 228 may extend from active region 232, as shown in FIG. 2A. WhenBL nodes 222 are connected to low voltages (e.g., about 0V to about 4V),there is sufficient isolation between the BL nodes 222 when common gate235 is turned off (e.g., by grounding the common gate contact 237).Accordingly, the need to form isolation regions to create separateactive regions for BL nodes 222 and/or the SRC nodes 237 can be avoided.

In some embodiments, similar to the common gate 235, the polysilicon forthe data gate 215 can extend beyond the active area 228. Duringread/program operations, the data gate 215 can be on to selectivelycouple the corresponding low-voltage circuitry (e.g., data cache 118and/or data register 120) to the respective bit line via BL node 222 andBL contact 227. During this time, the common gate 235 is off to isolatethe BL nodes 222 from the one or more SRC nodes 237, which can beconnected to a voltage source via respective SRC contacts 239. Duringerase operations, the data gate 215 can be off to isolate thelow-voltage circuitry (e.g., data cache 118 and/or data register 120)from the respective bit line. During this time, the common gate 235 ison to connect the BL nodes 222 to a voltage source (e.g., a high voltagesource) via SRC contacts 239 of the one or more SRC nodes 237. In someembodiments, as shown on FIG. 2B, an n+ mask layer 270 (inner mostshaded region) can be used to deposit n+ implant areas around the BLcontacts 227 and the SRC contacts 239. The n+ implant area provides aregion of low resistivity around the contacts to ensure better and morereliable connections.

As memory devices get smaller and/or denser such as in, for example, 3DNAND devices, it may be desirable to reduce the distance or pitchbetween the bit-lines of the memory array (e.g., memory array 104). Forexample, in some memory circuits, the BL contacts are arranged laterallyadjacent to each other in a straight line (also referred to herein as“non-offset BL line”). In such systems, the BL pitch is the distancebetween the BL contacts, and reducing the BL pitch means reducing thedistance between the BL contacts. However, the BL contacts may alreadybe at an effective distance that corresponds to a minimum effectivedistance. As used herein, “effective distance” means the shortestdistance between adjacent BL contacts or n+ implants disposed around theadjacent BL contacts, whichever distance is shorter. That is, theeffective distance may not necessarily be the shortest distance betweenthe BL contacts themselves. This is because n+ implants have lowresistivity, and thus the shortest distance between the n+ implantssurrounding the BL contacts can be the limiting factor when reducing theBL pitch. A “minimum effective distance,” as used herein, means that afurther reduction in the effective distance between the BL contacts willresult in adversely affecting BL-BL leakage (isolation) and/or breakdownvoltage (BV) to a point where the BL-BL leakage and/or BV falls outsidea predetermined design value for the memory device. Bit-line to bit-lineleakage affects the ability to properly read data from the bit-line andBV affects the maximum erase voltage and/or gate oxide reliability ofthe gate. For example, in some memory systems, a BL pitch of 38 nm cancorrespond to an effective distance of 5.76 nm. However, due tovariations in high volume manufacturing, further reductions in theeffective distance may not be possible while keeping the BV or the BL-BLleakage within the predetermined design value for the memory device.Thus, in traditional configurations where adjacent BL contacts aredisposed along a straight line, once the BL pitch of adjacent BLcontacts corresponds to the minimum effective distance and/or fallswithin variations of high volume manufacturing, there is little or no BLpitch margin to sacrifice and a further reduction in the pitch of theprotection circuits may not be achievable without exceeding designcriteria with respect to BL-BL leakage and/or BV. For example, it isbelieved that a BL pitch below 37 nm (corresponding to an effectivedistance of 5.44 nm) may not be achievable in traditional systems.

In some exemplary embodiments of the present disclosure, a BL contact227 (and/or corresponding n+ implant) in the circuit-protectionsubsystem 150 can be located on a non-offset BL line while a laterallyadjacent BL contact 227 (and/or corresponding n+ implant) can bedisposed in a location that is offset from the non-offset BL line by apredetermined distance (e.g., an offset greater than zero). Thepredetermined distance or offset can be in a direction that isperpendicular to the non-offset BL line. A direction parallel to thenon-offset BL line is referred herein as “width direction” and adirection perpendicular to the non-offset BL line can be referred toherein as “length direction.” For clarity, reference to the n+ implantmay be omitted in the following description when discussing the BLcontacts, but those skilled in the art understand that the BL contactsof the circuit-protection subsystem 150 can have surrounding n+ implants(or p+ implants or another type of doping depending on the type oftransistor) in some embodiments. By offsetting some BL contacts 227 inthe length direction, a BL pitch (“offset BL pitch”) in the widthdirection between the offset BL contact and a non-offset BL contact canbe less than a BL pitch (“non-offset BL pitch”) of circuit-protectiondevices having adjacent non-offset BL contacts. The arrow labeled “P” inFIG. 2A illustrates a BL pitch, which in this case, corresponds to anoffset BL pitch because the “B” BL contacts 227 are offset. Byoffsetting the “B” BL contact 227 (discussed further below), the offsetBL pitch (e.g., pitch P) can be less than a non-offset BL pitch and theeffective distance can remain the same between the offset and non-offsetBL pitches. In some embodiments, the offset BL pitch can be less thanthe minimum effective distance while keeping the actual effectivedistance between BL contacts at or above the minimum effective distance.

In some embodiments, more than one “B” BL contact 227 is offset andarranged on an offset bit-line connection line OBL (also referred toherein as “offset BL line OBL”) from an adjacent “A” BL contact 227 thatis not offset and arranged on a non-offset bit-line connection line NOBL(also referred to herein as “non-offset BL NOBL”). The BL contacts 227are arranged on the offset BL line OBL and non-offset BL line NOBL so asto form an offset stagger (or zig-zag) pattern along a width directionof circuit-protection subsystem 150. Accordingly, a set of BL contactscan be formed along a non-offset BL line NOBL and another set of BLcontacts can be formed along an offset BL line OBL. In some embodiments,a non-offset BL contact and a laterally adjacent offset BL contact canform a repeating alternating pattern. For example, as seen in FIGS. 2Aand 2B, the “B” BL contacts 227 (and corresponding BL nodes 222) ofprotection circuits 210 can be offset by a predetermined distance L1(also referred to herein as “offset distance L1”) in thelength-direction with respect to “A” BL contacts 227 (and correspondingBL nodes 222) of laterally adjacent protection circuits 210. In someexemplary embodiments, the BL contacts 227 of every other protectioncircuit 210 can be disposed at an offset distance L1. However, in otherembodiments, other offset distance patterns can be used such as, forexample, every second protection circuit 210, every third protectioncircuit 210, etc. In addition, in the exemplary embodiment of FIG. 2A,only a single offset distance (e.g., offset distance L1) is used in theoffset stagger pattern. However, in other embodiments, the BL contactsof the respective protection circuits can be disposed in any number ofpredetermined offset distance patterns. For example, the protectioncircuits 210 can be disposed in a staggered pattern (e.g., a repeatingstaggered pattern) in which a first BL contact has an offset of zero(e.g., on the non-offset BL line NOBL), the next BL contact has a firstpredetermined offset distance (e.g., offset distance L1), the next BLcontact has a second predetermined offset distance (not shown) that isdifferent from offset distance L1 and not zero, etc. In someembodiments, by offsetting the BL contact 227 of one or more protectioncircuits 210, the length of a circuit-protection subsystem 150 canincrease. However, because the pitch of the one or more protectioncircuits 210 can be reduced by offsetting the BL contacts, the overallarea of the circuit-protection subsystem 150 can be reduced despite apossible increase in the length. In addition, because the offset pitchis reduced in comparison to a non-offset BL pitch, the memory array 104can be denser and/or more memory cells can be added while shrinking thephysical size of the memory array 104 (or, at a minimum, withoutincreasing the physical size of the memory array 104). By arranging theBL contacts 227 to have an offset stagger pattern, the offset BL pitchof the protection circuits 210 can be reduced in comparison to anon-offset BL pitch while keeping the same effective distance betweenadjacent BL contacts 227. In some embodiments, while keeping theeffective distance between adjacent BL contacts 227 at or greater thanthe minimum effective distance, the BL pitch can be reduced to a valuethat is less than 37 nm, less than 36 nm, between 35 nm to 37 nm, orbetween 35 nm to 36 nm. In some embodiments, while keeping the effectivedistance between adjacent BL contacts 227 at or greater than the minimumeffective distance, the BL pitch can be reduced to a value that is lessthan the minimum effective distance.

In some embodiments, the offset distance L1 is set such that theeffective distance D1 (see FIG. 2B) between one or more adjacent BLcontacts 227 (e.g., between an offset BL contact and a non-offset BLcontact) equals the minimum effective distance. In some embodiments, theoffset distance L1 is set such that the effective distance D1 is in arange of 5 nm to 7 nm. As seen in FIG. 2B, the BL contacts 227 areformed in an area having rectangular cutouts in the polysilicon of thecommon gate 235. In the exemplary embodiment of FIG. 2B, the effectivedistance D1 is measured from a corner of an n+ implant of a non-offsetBL contact 227 to the nearest corner of an n+ implant of an offset BLcontact 227. Of course, the polysilicon cutout shapes are not limited torectangular shapes and can include other shapes such as, for example,circles, ovals, triangles, etc. In some embodiments, the offset distanceL1 is set such that an effective distance D2 between SRC contact 239 andone or more adjacent offset BL contacts 227 equals or exceeds theminimum effective distance. In some embodiments, the offset distance L1is set such that the effective distance D2 is in a range of 5 nm to 7nm. The effective distance D2 can be an outer part (e.g., corner oranother part of the perimeter) of an n+ implant of an SRC contact 239 tothe nearest outer part (e.g., corner or another part of the perimeter)of an adjacent n+ implant of an offset BL contact 227.

In some embodiments, the offset distance L1 is set such that theeffective distance D1 equals or exceeds the minimum effective distanceand the length AA1 of the active area 232 is set such that the effectivedistance D2 equals or exceeds the minimum effective distance. However,in some embodiments, to maintain an effective distance D2 that is at orgreater than the minimum effective distance, SRC nodes 237 can beselectively formed in regions of the common gate 235 that allow for aneffective distance that equals or exceeds the minimum effectivedistance. For example, as seen in FIGS. 2A and 2B, the SRC nodes 237 canbe disposed in locations where the opposing BL contacts 227 (andcorresponding BL nodes 222) are not offset (e.g., “A” BL contacts 227).The number of SRC nodes 237 and the corresponding SRC contacts 239 candepend on factors such as number of individual polysilicon gates thatform the continuous common gate 235, the number of BL nodes 222 that areoffset, the resistivity of the SRC contact 239 connections to the commongate 235, and/or reliability of the SRC contact 239 connections to thecommon gate 235. The number of SRC nodes 237 can be equal to or morethan the number of BL nodes 222. However, in other embodiments, thenumber of source nodes 237 can be less than the number of BL nodes 222.For example, in the embodiment of FIGS. 2A and 2B, the number of SRCnodes 237 will be about 25% of the number of BL nodes 222.

FIG. 2B illustrates an exemplary embodiment of an n+ mask used to formthe n+implants around BL contacts 227 and the SRC contacts 239. The n+mask layer 270 is overlapped by the polysilicon gate 235. In someexemplary embodiments, the n+ mask layer 270 can have a staggeredconfiguration that corresponds to the offset staggered pattern of the BLcontacts 227. For example, as seen in FIG. 2B, the n+ mask layer 270 hasan edge outline 272 (e.g., a step-wise edge outline) that matches theoffset stagger pattern on the BL contacts 227 of nodes 222. Based on then+ mask layer 270, the area around the location of one or more BLcontacts 227 and/or one or more SRC contacts 239 will include an n+implant. By configuring the edge of the n+ mask layer 270 to match theoffset stagger of the BL contacts 227, a distance D3 from the BLcontacts 227 to an exposed silicon portion of the node 222 remainsconstant between offset and non-offset BL nodes 222 of protectioncircuits 210.

As best seen in FIG. 2B, in some embodiments, the edge 229 of the activeareas 228 that are adjacent to the active area 232 can be formed tomatch the stagger (e.g., offset) of the active area 232 and/or the BLcontacts 227. For example, the edge 229 can be formed under thepolysilicon of the common gate 235 between the fingers 236 of the commongate 235 such that a distance D4 from the BL contacts 227 to the edge229 of the active area 228 for each of the protection circuits 210 is ata same value. In some embodiments, similar to the edge 229 of the activearea 228, the polysilicon edges 237 of the common gates 235 can alsohave a pattern that corresponds to the offset stagger pattern of the BLnodes 222 and/or BL contacts 227. Accordingly, in such embodiments,similar to the distance D4, a distance from the BL contact 227 to thepolysilicon edge 236 of the respective common gates 235 can be the samefor each protection circuit 210.

In some embodiments, a distance D5 from the BL contacts 227 to the datagate 215 can be equal between the protection circuits 210 in order tokeep the total resistance of the BL nodes 222 (e.g., resistance from thedata gate 215 to the respective BL contact 227) equal among theprotection circuits 210. Accordingly, in some embodiments, the positionof one or more data gates 215 can also be staggered by an offsetdistance (e.g., offset distance L1) that matches the offset staggerpattern of the respective BL contacts 227.

In some embodiments, if the data gates 215 are staggered, the LV nodes220 and/or LV contacts 225 can also be staggered (not shown) so that thelength of the LV nodes 220 and/or resistance of the LV nodes 220 can beset equal to each other. That is, the length of the LV nodes 220 anddata gate 215 can be equal in some embodiments. In some embodiments(e.g., as shown in FIG. 2A), the LV nodes 220 and the contacts 225 aredisposed in a straight line (e.g., not staggered) but the data gates 215are staggered. Accordingly, to the extent equal resistance between thelow-voltage nodes 220 is desired, the LV node 220 can be configured(e.g., composition or a physical dimension such as length, width, etc.)such that the resistance value is equal among the protection circuits210.

FIG. 3A illustrates a simplified block diagram of a portion of thecircuit-protection subsystem 150 that includes blocks representing thedate gates 215 and a simplified section illustrating the common gate235. As seen in FIGS. 2A and 3A, the protection circuit 210 are mirroredalong a centerline of the circuit-protection subsystem 150 containingthe common gate 235. In this embodiment, the n+ implant in the BL nodes222 are equal due to the step-wise (or staggered) n+ mask edge 330.Accordingly, the active areas 228 can also be staggered to maintain anequal resistance as discussed above. As seen in FIG. 3A, the common gatesection 235 includes one or more p-well implant layers 310. The p-wellimplant layers 310 can be disposed between the BL nodes 222 and/or theSRC nodes 237 and serve to define the boundaries between the BL nodes222 and/or the boundaries between BL nodes 222 and the SRC nodes 237. Insome embodiments, the p-well implant layers 310 are disposedperpendicular to a line corresponding to the effective distance betweenthe n+ implants of adjacent BL nodes 222 (e.g., line 320) and/or a linecorresponding to the shortest distance between the n+ implants of SRCnode 237 and an adjacent BL node 222 (e.g., line 322). In otherembodiments (not shown), the p-well implants are disposed in straightlines between the BL nodes 222 and/or between BL nodes 222 and the SRCnodes 237 so that the p-well implants intersect at 90-degrees to eachother. A portion of p-well implant layer 310 can be doped (e.g., lightlydoped) to have p-type conductivity, where the doped portion has adesired threshold voltage (Vt) for the channel of the field-effecttransistor formed between the BL nodes 222 and/or the channel of thefield-effect transistor formed between the BL nodes 222 and the SRC node237.

FIG. 3B illustrates a simplified block diagram of a portion of anotherembodiment of the circuit-protection subsystem. The circuit-protectionsubsystem 150′ includes a block illustrating the data gates 215 and asimplified section illustrating a portion of the common gate 235. Inthis embodiment, the n+ mask layer 340 is configured so as to have astraight edge (see dotted line). Accordingly, unlike the embodiment ofFIG. 3A, the edge of the n+ mask layer 340 does not include a staggerthat matches the offsets of the “B” BL nodes 222. Because of thestraight edge, the n+ implant distribution 342 (see shaded region) ineach of the of BL nodes 222 are not equal and the distance from the BLcontacts 227 to the edge of the n+ mask layer 340 will be different.However, because the BL nodes 222 include a highly doped n+ implant area342, any difference in the resistances from the BL contact 227 to edgethe n+ mask layer 340 between the protection circuits 210 is negligible.That is, only the resistance of the non-n+ doped regions of the activearea 228 can be considered when configuring the protection circuits.Accordingly, in some embodiments, the protection circuits 210 can beconfigured such that the data gates 215 are not staggered and a distanceD6 between the data gates 215 and the edge of the n+ mask layer 340 isset to be the same for each of the protection circuits 210. The lengthfrom the BL contact 227 and the exposed portion of the active area 228and/or to the data gates 215 not set to be equal, but this is not aproblem because the n+ implant areas have negligible differences inresistance. Of course, to the extent the resistance of the active areas228 would benefit from further equalization between the protectioncircuits 210, the geometry (e.g., width, length, and/or shape) and/orcomposition (e.g., n/p doping) of each active area 228 can be changedsuch that the resistances are equal.

As discussed above, in some embodiments, the edge of the n+ implantlayer 340 is not staggered to match a stagger of the BL contacts 227. Insuch embodiments, however, it is possible that the effective distancebetween adjacent BL contacts 227 may no longer be a limiting dimensionwith respect to the pitch of the protection circuit 210. Instead, insome embodiments, it is possible that a distance X1 between the BL nodes222 in the fingers 345 is configured to be at or greater than theminimum effective distance in order to ensure that the bit-line tobit-line isolation and/or breakdown voltage falls within a predetermineddesign value for the memory device. Accordingly, to ensure the distanceX1 is at or greater than the minimum effective distance, the polysiliconof the common gate 235 can extend into the active area 228 of the offsetBL nodes 222. For example, as seen in FIG. 3B, polysilicon tabs 360extend into the active areas 228 of the “B” or non-offset protectioncircuits 210 to ensure the distance X1 is at or greater than the minimumeffective distance.

FIG. 3C illustrates another embodiment of the present disclosure. Theembodiment in FIG. 3C is similar to the embodiment of FIG. 3B withrespect to the n+ mask layer, which has a straight edge 340. However,instead of a single polysilicon gate (e.g., common gate 235), thecircuit-protection subsystem 150″ includes a shared gate 235 a″ for theprotection circuits 210 in line 212 and a shared gate 235 b″ for theprotection circuits 210 in line 214. The shared gates 235 a″ and 235 b″can be disposed on either side of a continuous source area 335 that isdisposed between the protection circuits 210 of line 212 and theprotection circuits 210 of line 214. In some embodiments, the continuoussource area 335 can be doped with an n+ implant layer. In someembodiments, the protection circuits 210 on one side of the continuoussource area 335 can be offset in comparison to the protection circuits210 on the other side of the continuous source area 335. In someembodiments, the offset of the protection circuits is such that anon-offset BL node 222 of the shared gate 235 a″ is aligned with anoffset BL node 222 of the shared gate 235 b″ and vice versa. That is,the protection circuits 210 in the circuit-protection subsystem 150″ arenot mirrored along a centerline extending through the SRC nodes 237 likein circuit-protection subsystem 150 discussed above. In someembodiments, each of the shared gates 235 a″ and 235 b″ can include oneor more SRC nodes 237″, with each SRC node 237″ having a contact 239″.In some embodiments, one or more SRC nodes 237″ with the respective SRCcontacts 239″ can be disposed in the continuous source area 335 betweenopposing offset/non-offset pairs of BL nodes 222″. For example, as seenin FIG. 3C, an SRC node 237″ can be disposed between a non-offset BLnode 222″ and an offset BL node 222″ on the opposing shared gate. Insome embodiments, the continuous source area 335 and/or the SRC nodes237″ include an n+ implant. By using an offset configuration for theopposing protection circuits 210, an SRC node 237 with corresponding SRCcontact 239 can be disposed between every pair of opposing protectioncircuits 210. Thus, while circuit-protection subsystem 150″ may belarger than circuit-protection subsystems 150 and 150′, the greaternumber of source contacts in circuit-protection subsystem 150″ canprovide more reliability. FIG. 3C shows a configuration in which acontinuous source area 335 is added to circuit-protection subsystem 150″that is similar in configuration to circuit-protection subsystem 150′.However, those skilled in the art will understand that a continuoussource area 335 can also be added to a circuit-protection device that issimilar in configuration to circuit-protection subsystem 150. Inaddition, those skilled in the art will understand that the otherfeatures of circuit-protection devices 150 and/or 150′, discussed above,as be included in circuit-protection subsystem 150″, as appropriate, andthus, for brevity, will not be repeated.

In the embodiments discussed above, the openings in the polysiliconlayer for the BL contacts and SRC contacts are shown having shapes withright-angles (e.g., rectangles or a portion thereof). However, theopenings can have other types of shapes, such as for example,multi-sided shapes, circles, ovals, portions thereof, etc. For example,as seen in FIG. 3D, in some embodiments, the opening in the polysiliconfor BL contact 227 and/or SRC contact 239 can include facets 370. Thefacets 370 can be disposed so as to increase the effective distancebetween adjacent BL contacts 227 (not shown) and/or the effectivedistance D2 between the BL contact 227 and the SRC contact 239 incomparison to openings that have right-angles as shown in FIGS. 2A and2B.

In some 3D-type memory devices, memory subsystems including controllogic (e.g., control logic 116) and/or page buffers (e.g., cacheregister 118) can be disposed under the memory array (e.g., memory array104). This arrangement, known as CMOS under array (CUA), allows thememory subsystem to be smaller than systems in which the control logicand page buffer are located adjacent to the memory array. However, evenconfigured as a CUA, there can be a limit with respect to how muchsmaller a memory device can get due to how some cache memory latches arefabricated. In some cache memory latches, the NMOS and PMOS components(e.g., p-channel low-voltage PLV and n-channel low-voltage NLV) of theCMOS inverters that make up the latch are formed in separate wells. Eventhough the wells may be closely spaced, the spacing requirements for thecomponents will mean a greater area for the CMOS inverters than if thecomponents are formed in the same well. The separate remote wells alsomean that the metal routing between the components can get congested andcomplicates the ability to shrink the CUA.

To reduce the pitch of the latches and thus the size of the page buffer,exemplary embodiments of the present disclosure include integrated CMOSinverters that can be incorporated into a NAND latch to create a memorycell (e.g., an SRAM cell). The integrated CMOS inverter can include aPMOS transistor and an NMOS transistor that share a common active area.Because the NMOS and/or PMOS transistors are floating body, an n-wellimplant is not needed. Accordingly, the integrated CMOS inverter usesless space than a traditional CMOS inverter. In some embodiments, thePMOS transistor and/or the NMOS transistor can be formed as a verticaltransistor. In some embodiments, the integrated CMOS inverter caninclude a common gate, which can eliminate the need to connect theseparate gates of each component. When one or both transistors arevertical, the integrated CMOS inverter of the present disclosure allowsfor neighboring CMOS inverters to be in close proximity without concernfor polysilicon-polysilicon spacing of the gate end caps. Thus, the needfor gaps between gate end caps (nibbles) that can exist in traditionalpage buffer latch layouts can be eliminated.

FIG. 4A illustrates a cross-sectional view of an integrated inverter 400that includes a planar NMOS transistor 410 and a vertical PMOStransistor 440 with a common output contact 430. The integrated inverter400 can be disposed on a silicon substrate 402. The active area of theintegrated inverter 400 is common to both the NMOS and PMOS transistorsand can be defined by shallow-trench isolation 460 on each side of theintegrated inverter 400. As seen in FIG. 4A, the NMOS transistor 410includes an NMOS source 412 and a NMOS drain 422, which can be ann+diffusion layers disposed into the silicon substrate 402. One or moremetal layers (e.g., a tungsten layers) can be disposed on the NMOSsource 412 to create an NMOS source contact 414. One or more metallayers (e.g., a tungsten layers) can be disposed on the NMOS drain 422,and the metal layer(s) can also connect to the PMOS drain 444 to form acommon output contact 430. A channel 413 can be disposed between NMOSsource 412 and NMOS drain 422. A portion of channel 413 can be dopedwith a different (e.g., higher) conductivity than that of the p-typesubstrate 402 such that the doped portion has a desired thresholdvoltage (Vt). The NMOS source 412 can be connected to ground potentialGND via the NMOS source contact 414. The NMOS transistor 410 can alsoinclude a silicon oxide layer 416 disposed above the source 412 anddrain 422. Between source 412 and the drain 422, the silicon oxide layer416 acts as the gate oxide for the planar NMOS transistor. The siliconoxide layer 416 can be deposited on the silicon substrate 402 so as tosurround the metal layer 414. In addition, one or more silicon oxidelayers can be disposed on the silicon oxide layer 416 so as to isolatethe metal layer 414 from the surrounding components. A gate 418comprised of one or more layers of polysilicon and/or WSix (tungstensilicide) can be disposed on top of the silicon oxide layer 416. In someembodiments, the gate 418 can have a gate-all-around (GAA) design thatis common to both the planar NMOS transistor 410 and the vertical PMOStransistor 440. One or more metal layers (e.g., a tungsten layers) canbe disposed on the common gate 418 to serve as the input contact 420(Vin) to the inverter 400.

The vertical PMOS transistor 440 includes a PMOS source 448, which canbe an p+ implant layer, disposed on a channel 450. The channel 450 canbe comprised of one or more layers of polysilicon, which can be n-typepolysilicon. The channel 450 can be disposed on a PMOS drain 444, whichcan be a p+ diffusion layer. The PMOS drain 444 can be formed on ann-type diffusion layer 404, which can be formed on the substrate 402.The PMOS drain 444 can connect to the common output contact 430, whichcan be made of one or more metal layers (e.g., a tungsten layers). Thus,the common output contact 430 connects to both the NMOS drain 422 andthe PMOS drain 444. The silicon oxide layer 416 can be deposited on thesilicon substrate 402 so as to surround the metal of the common outputcontact 430. In addition, one or more silicon oxide layers 424 can bedisposed on the silicon oxide layer 416 so as to surround the commonoutput 430 and isolate the common output 430 from the common gate 418.In some embodiments, the composition of the silicon oxide layer 424 andthe silicon oxide layer 416 can be the same. One or more metal layers(e.g., a tungsten layer) can be disposed on the PMOS source 448 to serveas the PMOS source contact 452. The PMOS source 448 can be connected toVcc potential (e.g., 3.5 volts) via the PMOS source contact 452. Thesilicon oxide layer 416 can be disposed on the silicon substrate 402 soas to surround the channel 450. One or more lateral gate oxide layers446 can be disposed on the silicon oxide layer 416 so as to surround thechannel 450 (see also FIG. 4B). In some embodiments, the composition ofthe lateral gate oxide layer 446 and the silicon oxide layer 416 can bethe same.

FIG. 4B is a top view of the inverter 400. As seen FIG. 4B, the GAA-typegate 418 covers nearly all of the inverter 400. The inverter 400 can beconfigured with one or more NMOS source contacts 414, which can beisolated form the gate 418 by one or more silicon oxide layers 416. Inthe embodiment of FIG. 4B, there are two contacts 414, but any number ofcontacts can be used based on design resistivity, reliability of theconnections and complexity of the connections. For example, if only onecontact is used and it is defective, the inverter 400 and, thus thememory cell, will be unusable. However, forming a large number ofcontacts may not be economical or technically feasible. Similarly,although shown with two contact each, there can be one or more contactsformed for the input contact 420 and/or common output contact 430. Theinput contacts 420 are connected to the gate 418, while the commonoutput contacts 430 are isolated from the gate 418 by one or moresilicon oxide layers 424. As shown in FIG. 4B, a single PMOS sourcecontact 452 is formed on the vertical PMOS transistor 440. However, insome embodiments, more than one PMOS source contact can be formed. ThePMOS source 448 is shown having a rectangular column (e.g., squarecolumn) shape in FIGS. 4A and 4B. The channel 450, which is hidden, canalso have a rectangular column (e.g., square column) shape. However, thePMOS source 448 and/or the channel 450 can have other shapes such as,for example, a cylindrical column shape. One or more gate oxide layers446 can surround the channel 450 to isolate the channel 450 form thecommon gate 418 (see also FIG. 4A). The gate oxide layers 446 can have ageometry that corresponds to that of the channel 450. For example, ifthe channel 450 is a rectangular column, the gate oxide layers 446 canbe a rectangular tube, if the if the channel 450 is a cylindricalcolumn, the gate oxide layers 446 can be a cylindrical tube, and so on.

In operation, when the input contact 420 (Vin) has a high signal (e.g.,high potential), the GAA-type common gate 418 is also at a highpotential. With the gate 418 high, the planar NMOS transistor 410 is onand vertical PMOS transistor 440 is off. With NMOS transistor 410 on,the NMOS source 412, which is at ground potential GND via NMOS sourcecontact 414, is connected to common output contact 430 (Vout) viachannel 413 and NMOS drain 422. Accordingly, when the input contact 420(Vin) has a high signal, the common output contact 430 (Vout) has lowsignal. When the input contact 420 (Vin) has a low signal (e.g., lowpotential), the gate 418 is also at a low potential. With the gate 418low, the planar NMOS transistor 410 is off and vertical PMOS transistor440 is on. With PMOS transistor 410 on, the PMOS source 448, which is atVcc potential via PMOS source contact 452, is connected to the commonoutput contact 430 (Vout) via channel 450 and PMOS drain 444.Accordingly, when the input contact 420 (Vin) has a low signal, thecommon output contact 430 (Vout) has high signal. Thus, the planarNMOS-vertical PMOS inverter 400 will behave similar to a traditionalplanar NMOS-planar PMOS inverter but will take up less space because,unlike all-planar CMOS inverters, separate wells are not needed.Although a planar NMOS and a vertical PMOS is described above, thoseskilled in the art understand that a planar PMOS and a vertical NMOSwill have a similar configuration but with the p-type implants andn-type implants reversed. Accordingly, for brevity, a discussion of aninverter with a planar PMOS and a vertical NMOS is omitted.

FIG. 5A illustrates a cross-sectional view of an integrated inverter 500that includes a vertical PMOS transistor 510 and a vertical NMOStransistor 540. The integrated inverter 500 can be disposed on a siliconsubstrate 502. The active area of the integrated inverter 500 is commonto both the PMOS and MMOS transistors and can be defined byshallow-trench isolation 560 on each side of the integrated inverter500. The vertical PMOS transistor 510 and a vertical NMOS transistor 540include a common output contact 530 and a common gate 518. The verticalPMOS transistor 510 includes a PMOS source 512, which can be an p+implant layer, disposed on a channel 555. The channel 555 can becomprised of one or more layers of polysilicon, which can be n-typepolysilicon. The channel 555 can be disposed on a PMOS drain 522, whichcan be a p+ diffusion layer disposed into the silicon substrate 502,which can be an n-type well. The silicon oxide layer 516 can be disposedon the silicon substrate 502 so as to surround the channel 555. The PMOSdrain 522 and an NMOS drain 544 can be connect to a common outputcontact 530, which can be made of one or more metal layers (e.g., atungsten layers). Thus, the common output contact 530 connects to boththe PMOS drain 522 and the NMOS drain 544. The silicon oxide layer 516can be deposited on the silicon substrate 502 so as to surround themetal of the common output contact 530. In addition, one or more siliconoxide layers 524 can be disposed on the silicon oxide layer 516 so as tosurround the common output 530 and isolate the common output 530 from acommon gate 518. In some embodiments, the composition of the siliconoxide layer 516 and the silicon oxide layers 524 can be the same. One ormore metal layers (e.g., a tungsten layer) can be disposed on the PMOSsource 512 to serve as the PMOS source contact 514. The PMOS source 512can be connected to Vcc potential (e.g., 3.5 volts) via the PMOS sourcecontact 514. One or more lateral gate oxide layers 513 can be disposedon the silicon oxide layer 516 so as to surround the channel 555. Thecommon gate 518 can be comprised of one or more layers of polysiliconand/or WSix (tungsten silicide). The common gate 518 can be disposed ontop of the silicon oxide layer 516. The common gate 518 can be agate-all-around design. One or more metal layers (e.g., a tungstenlayers) can be disposed on the GAA-type gate 518 to serve as the inputcontact 520 (Vin) to the inverter 500.

The vertical NMOS transistor 540 of the integrated inverter 500 includesan NMOS source 548, which can be an n+ implant layer, disposed on achannel 550. The channel 550 can be comprised of one or more layers ofpolysilicon, which can be p-type polysilicon. The channel 550 can bedisposed on an NMOS drain 544, which can be a n+ diffusion layerdisposed into a p-type diffusion layer 504. The p-type diffusion layer504 can be disposed in the silicon substrate 502. The NMOS drain 544 canbe connected to the common output contact 530. One or more metal layers(e.g., a tungsten layer) can be disposed on the NMOS source 548 to serveas the NMOS source contact 552. The NMOS source 548 can be connected toground potential (GND) via the NMOS source contact 552. The siliconoxide layer 516 can be disposed on the silicon substrate 502 so as tosurround the channel 550. One or more lateral gate oxide layers 546 canbe disposed on the silicon oxide layer 516 so as to surround the channel550.

FIG. 5B is a top view of the inverter 500. As seen FIG. 5B, the GAA-typegate 518 covers nearly all of the inverter 500. The inverter 500 can beconfigured with a single PMOS source contacts 514 that is formed on thevertical PMOS transistor 510. However, in some embodiments, more thanone PMOS source contact can be formed. That is, while there is onecontact shown in FIG. 5B, any number of contacts can be used based ondesign resistivity, reliability of the connections and complexity of theconnections. Similarly, although shown with two contacts each, there canbe one or more contacts formed for the input contact 520 and/or commonoutput contact 530. The input contacts 520 are connected to the gate518, while the common output contacts 530 are isolated from the gate 518by one or more silicon oxide layers 524. As sown in FIG. 5B, a singleNMOS source contact 552 is formed on the vertical NMOS transistor 540.However, like the PMOS source contact, in some embodiments, more thanone NMOS source contact can be formed. The PMOS source 512 and the NMOSsource 548 are shown having a rectangular column (e.g., square column)shape in FIGS. 5A and 5B. One or both of the respective channels 555 and550, which are hidden under the sources 512 and 548, can also haverectangular column (e.g., square column) shapes. However, one or both ofthe PMOS source 512 and the NMOS source 548 and/or one or both of thechannels 555 and 550 can have other shapes such as, for example,cylindrical column shapes. One or more gate oxide layers 513 and 546 cansurround the respective channels 555 and 550. Of course, the gate oxidelayers 513 and 546 can have geometries that correspond to the respectivechannels 555 and 550. For example, if one or both of the channels 555,550 has a rectangular column configuration, the respective gate oxidelayers 513, 546 can be a rectangular tube, if one or both of thechannels 555, 550 has a cylindrical column configuration, the respectivegate oxide layers 513, 546 can be a cylindrical tube, and so on.

In operation, when the input contact 520 (Vin) has a high signal (e.g.,high potential), the GAA-type common gate 518 also has a high potential.With the common gate 518 high, the NMOS transistor 540 is on and thePMOS transistor 510 is off. With the NMOS transistor 540 on, the NMOSsource 458, which is at ground potential GND via PMOS source contact552, is connected to the common output contact 530 (Vout) via channel550 and PMOS drain 544. Accordingly, when the input contact 520 (Vin)has a high signal, the common output contact 530 (Vout) has a lowsignal. When the input contact 520 (Vin) has a low signal (e.g., lowpotential), the gate 518 also has a low potential. With the common gate518 low, the NMOS transistor 540 is off and the PMOS transistor 510 ison. With the PMOS transistor 510 on, the PMOS source 512, which is atVcc potential via PMOS source contact 514, is connected to common outputcontact 530 (Vout) via channel 555 and PMOS drain 522. Accordingly, whenthe input contact 520 (Vin) has a low signal, the common output contact530 (Vout) has a high signal. The vertical NMOS-vertical PMOS inverter500 as disclosed above will behave similar to a traditional planarNMOS-planar PMOS inverter but will take up less space because separatewells are not needed. While a vertical-vertical inverter (e.g., inverter500) can be more compact than a planar-vertical (e.g., inverter 400), insome cases inverter 400 can be more economical. Because one of theinverters is planar, a portion of the traditional fabrication processcan be used when manufacturing planar-vertical inverters.

FIG. 6A illustrates a memory cell 600, e.g., an SRAM cell, having twointegrated inverters 610 a,b that can be, for example, the same asinverter 500 having a PMOS transistor and an NMOS transistor, asdiscussed above. As seen in FIG. 6A, the integrated inverters 610 a,bare oriented such that the input contact(s) 620 a of inverter 610 aaligns (e.g., linearly aligns) with the output contact(s) 630 b ofinverter 610 b, and the input contact(s) 620 b of inverter 610 b aligns(e.g., linearly aligns) with the output contact(s) 630 a of inverter 610a. In some embodiments, conductive contact strips 640 a and 640 b (e.g.,metal layers) can be disposed such that the input contact(s) 620 a and620 b are connected to output contacts 630 b and 630 a, respectively. Byusing an integrated inverter configuration, the routing of the contactstrips between the connections of the inverters is direct (e.g., linear)and less congested, which allows for a more compact cache configuration.

FIG. 6B illustrates a memory cell 600′, e.g., an SRAM cell, having twointegrated inverters 610 a′ and 610 b′. Integrated inverter 610 a′ canbe the same as integrated inverter 500 discussed above. Inverter 610 b′can be similar to inverter 500 except that the orientation of inputcontact(s) 620 b′ and output contact(s) 630 b′ are reversed incomparison to the input contact(s) 620 a′ and output contact(s) 630 a′of integrated inverter 610 a′. By reversing the input and outputcontacts, one of the integrated inverters does not have to be rotated180 degrees (as in the case of FIG. 6A) for the input contact(s) 620 a′and 620 b′ to line up (e.g., linearly align) with the opposing outputcontact(s) 630 b′ and 630 a′, respectively, for easy strapping. In thememory cell 600′, the PMOS transistors are aligned (e.g., linearlyaligned) between the two inverters and the NMOS transistors are aligned(e.g., linearly aligned) between the two inverters. Accordingly, becauselike transistors are aligned, fabrication of the memory cells 600′ canbe less complex and easier than if like transistors are not aligned,while still keeping the advantage of the simplified and less congestedrouting.

FIGS. 6C and 6D illustrate alternative layout and interconnectionarrangements for a memory cell (e.g., an SRAM cell) with integratedinverters. In the embodiment of FIG. 6C, the memory cell 650 includesintegrated inverters 660 a and 660 b. Integrated inverter 660 a can besimilar to integrated inverter 500 but the silicon layer 665 a aroundthe output contact 663 a extends to an edge of the active area of theintegrated inverter 660 a. Integrated inverter 660 b can also be thesame as integrated 660 a in some embodiments. However, in the embodimentof FIG. 6C, integrated inverter 660 b is similar to integrated inverter500′ with respect to the arrangement of the PMOS and NMOS inverters, butin integrated inverter 660 b, the silicon layer 665 b around the outputcontact 663 b extends to an edge of the active area of the integratedinverter 660 b. As seen in FIG. 6C, the connections between theintegrated inverters can be done using a polysilicon connection ratherthan a metal connection. For example, a polysilicon connection strip 664a can extend from the polysilicon gate layer 668 a corresponding toinput contact(s) 662 a to the extended silicon layer 665 b correspondingto output contact 663 b. Similarly, a polysilicon connection strip 664 bcan extend from the polysilicon gate layer 668 b corresponding to inputcontact(s) 662 b to the extended silicon layer 665 a corresponding tooutput contact 663 a. For example, the polysilicon connection strips 664a and 664 b can be stitched to respective output contacts 663 b and 663a. That is, the polysilicon connection strip is formed onto therespective extended silicon layer and the corresponding output contact(e.g., elongated output contact) is formed so as to overlap a portion ofthe polysilicon connection strip. For example, overlap portion 667 arepresents the overlap of contact 663 a onto polysilicon connectionstrip 664 b, and overlap portion 667 b represents the overlap of contact663 b onto polysilicon connection strip 664 a.

FIG. 6D illustrates an embodiment of a memory cell (e.g., an SRAM cell).The memory cell 680 includes integrated inverters 690 a and 690 b. ThePMOS and NMOS transistors are similar in arrangement to that ofintegrated inverter 500. However, the input and output for theintegrated inverter is formed on a same side of the PMOS and NMOStransistors instead of between the transistors. For example, as seen inFIG. 6D, a polysilicon gate section 692 a corresponding to an inputcontact and a silicon oxide section 693 a corresponding to an outputcontact are formed on a same side of the PMOS and NMOS transistors ofthe integrated inverter 690 a. Similarly, a polysilicon gate section 692b corresponding to an input contact and a silicon oxide section 693 bcorresponding to an output contact are formed on a same side of the PMOSand NMOS transistors of the integrated inverter 690 b. In the embodimentof FIG. 6D, the arrangement of the PMOS and NMOS transistors is the samefor both the integrated transistors 690 a and 690 b thus one of theinverters is rotated 180 degrees. However, in other embodiments, thearrangement of the PMOS and NMOS transistors can be revered inintegrated transistor 690 b so that the transistors of the same type arelinearly aligned similar to the embodiment of FIG. 6B. In someembodiments, the input polysilicon gate sections 692 a and 692 b can bestitched into the respective output silicon oxide section 693 b and 693a using corresponding contact strips 695 a and 695 b (e.g., an elongatedoutput contact). The contact strips can be, for example, polysilicon,metal, and/or another appropriate material. Although integratedinverters having vertical PMOS and vertical NMOS configurations areshown in FIGS. 6A to 6D, those skilled in the art will recognize thatintegrated inverter 400 can be similarly arranged to form a compactmemory cell. Accordingly, for brevity, discussion of the connections ina planar/vertical memory cell is omitted.

As discussed above with reference to FIG. 6D, the input connection andthe output connection can be disposed on a same side of the integratedinverter so that corresponding inverters can be conveniently andcompactly connected using, e.g., an elongated contact. However, insteadof an elongated contact, in some embodiments, a modified pillar channelcan be used to directly connect the input polysilicon gate layer of oneof the integrated inverters to the output silicon layer of the otherintegrated inverter. For example, FIGS. 7A and 7B illustrate twoembodiments of a pillar channel contact that can be used in place of anelongated contact configuration of FIG. 6D. In the embodiment of FIG.7A, the input pillar connection of an integrated inverter 710 isdeposited over an output silicon layer 742 of another integratedinverter 740. To form the pillar channel connection 720, an opening inthe protective mask for forming the pillar channel 720 is larger thanthe diameter of the pillar channel 720 so that, when the polysilicon forthe pillar channel 720 is deposited, the channel polysilicon overlaps aWSix layer 722 and/or a polysilicon layer 724 that corresponds to theinput connection. In some embodiments, only one of the WSix layer 722 orthe polysilicon layer 724 may be formed on top of a silicon oxide layer726. Once the pillar channel 720 is formed, an electrical connectionwith current path 730 is formed between the input WSix/polysilicon layer722/724 of the inverter 710 to the output silicon 742 of the inverter740. In the embodiment of FIG. 7A, a layer of sidewall silicon oxide 728is formed such that the current path 730 is the full length of thepillar channel 720. In the embodiment of FIG. 8B, a pillar channel 752of an integrated inverter 750 is formed without a sidewall silicon oxideso that the input WSix/polysilicon layer 722/724 of the inverter 750comes into direct electrical contact with the polysilicon of the pillarchannel 752 and a shorter current path 732 is formed between inverter750 and the output silicon 742 of the inverter 740. In some embodiments,the diameters of the pillar channel 720 and/or 752 are made as small aspossible to keep the capacitance as small as possible while maintain areliable electrical connection.

FIGS. 8A-8C illustrate a simplified high-level fabrication process foran integrated inverter having a planar NMOS and a vertical PMOS. Thoseskilled in that understand the details of a fabrication process for aCMOS inverter and thus, for brevity, details related to photoresistlayers, masks, chemical and/or plasma etching, and other known detailsare omitted. Prior to the deposition of the silicon oxide layer 808, ashallow n-type implant layer 804 is deposited onto a p-type substrate802. The n-type implant layer 804 deposition provides for isolation ofthe vertical PMOS transistor. A p+ implant layer 806 can then be addedon top of the n-type implant layer 804 to act as the drain for thevertical PMOS transistor. The arrangement of the n-type implant layer804 and the p+ implant layer 806 is such that the n-type implant layerarea is larger and extends out beyond the area of the p+ implant layer806. For example, in some embodiments, the n-type implant layer 804 isangled and/or a resist trim etch is performed after p+ implant layer 806such that the n-type implant area extends out farther than the p+implant layer area. In the case of a vertical NMOS transistor, only ann+ implant layer, which acts as a drain, may be deposited on the p-typesubstrate. For a vertical CMOS inverter, the steps for the vertical PMOStransistor and the vertical NMOS transistor discussed above can beperformed. After the p+ implant layer 806 is deposited, one or moresilicon oxide layers 808, one or more polysilicon gate layers 810,and/or one or more WSix (e.g., tungsten silicide) gate layers 812 can bedeposited. The layers are added in the appropriate sequence and with anetching of at least the gate layers 810/812 to produce an intermediatecomponent in which the silicon oxide layer 808 deposited over the activearea is covered by the polysilicon gate layer 810 and the WSix gatelayer 812 and the silicon oxide layer 808 in the STI areas 830 arecovered by the WSix gate layer 812.

As seen in FIG. 8B, a protective layer 814 with an opening for thechannel 818 for the vertical PMOS transistor is deposited over the WSixgate layer 814. The thickness of the protective layer 814 can be basedon a desired amount that the polysilicon of the vertical channel shouldextend above the WSix gate layer 812. After deposition of the protectivelayer 814, an etch is performed on the Wsix and polysilicon gate layers812/814 to create the hole for the channel 818 of the vertical PMOStransistor. One or more layers of silicon oxide are deposited, and agate sidewall etch is performed to create a hole and expose the bottomto the p+ implant layer 806. With the creation of the lateral gate 816,one or more layers of polysilicon is deposited to create the channel818. The intermediate component is then subject to chemical mechanicalpolishing (CMP) the top of protective layer 814. The protective layer814 is then etched away (not shown in FIG. 8B).

After the protective layer 814 is etched away, as seen in FIG. 8C, agate etch is performed to define the common gate configuration whichincludes an opening for the output contact area (Vout). The n+ implantlayers 822 and 824 corresponding to the source and drain, respectively,can be deposited after the gate etching process. In addition, a p+implant layer 820, corresponding to the source of vertical PMOStransistor, can be deposited on the channel 818. After silicon oxidebuild up and subsequent etching of the openings for the ground GND andVout contacts, one or more layers of metal (e.g., tungsten) can bedeposited to form the source Vcc, ground GND, Vin and Vout contacts.

In some embodiments where the integrated CMOS inverter includes a planarNMOS and a vertical PMOS, the fabrication of the vertical PMOS can beaccomplished by recess etching the silicon substrate to create the PMOSchannel (e.g., a silicon mesa) rather than forming the channel bysilicon deposition as discussed above. As seen in FIG. 9A, an n-typesilicon layer 908 is formed over a p-type silicon substrate 902. As seenin FIG. 9B, a hard mask 912 is deposited over an area that correspondsto the n-type channel for the PMOS transistor, and the n-type siliconlayer 908 is then etched until the p-type substrate 902 is reached. Dueto the hard mask 912, a mesa 910 that corresponds to a n-type channelfor a PMOS transistor is formed. After the etching process, an n-typetub is formed under a p-type implant layer. That is, one or more n-typedopant layers are deposited into the p-type substrate under the mesa 910to create an n-type implant 904. The n-type dopant layers of the n-typeimplant 904 can be angled such that the n-type implant 904 encases ap-type implant 906 that has been deposited under the mesa 910.

As seen in FIG. 9C, after the etching process, a photoresist layer 922is added with openings in the photoresist layer 922 that correspond tothe drain of the PMOS transistor. The fabrication process then includesadding a p+ implant layer 914 into the p-type implant 906 (see FIG. 9B).As seen in FIG. 9D, the formation process includes depositing one ormore silicon oxide layers 916 followed by one or more polysilicon layers918 and one or more additional silicon oxide layers 920. In addition,each STI is masked and etched. The silicon oxide layers 920 can includesacrificial oxide with stripe to fix any etch-induced damage. As seen inFIG. 9E, the silicon oxide 921 at the STI is recessed below the top ofthe polysilicon layer 918. One or more WSix layers 924 can be depositedon top of the poly silicon layer 918. In some embodiments, additionalthin layer(s) of polysilicon can be deposited prior to the WSix layer924 based on the topology of the active area-STI interface.

After depositing the WSix layer 924, as seen in FIG. 9F, an etch isperformed to expose the hard mask 912 on the mesa 910, and to expose thedrain 930 and source 928 areas of an NMOS transistor on top of thesilicon substrate 902. A further wet etch can be performed to remove thehard mask 912 from the top of the mesa 910. In addition, usingappropriate masking, a p+ implant deposition can be performed to createthe source 926 of the PMOS transistor, and an n+ implant deposition canbe performed to create the source 928 and the drain 930 of the NMOStransistor. After the backend oxide fill and a CMP, as seen in FIG. 9G,the source contact (e.g., ground GND) for the NMOS source 928, the inputcontact (e.g., Vin) for common gate 924, the output contact (e.g., Vout)bridging the n+/p+ interface between NMOS drain 930 and PMOS drain 914,and the source contact (e.g., Vcc) for the PMOS source 926 can bedeposited.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement that is calculated to achieve a similar (e.g., thesame) purpose may be substituted for the specific embodiments shown. Forexample, for other embodiments, enhancement-mode-field-effecttransistors may be substituted for the depletion-mode-field-effecttransistors described above. For example,metal-gate-enhancement-mode-field-effect transistors may be substitutedfor the metal-gate-depletion-mode-field-effect transistors, andlateral-gate-enhancement-mode-field-effect transistors may besubstituted for the lateral-gate-depletion-mode-field-effecttransistors. Accordingly, this application is intended to cover anyadaptations or variations of the embodiments.

The above detailed descriptions of embodiments of the technology are notintended to be exhaustive or to limit the technology to the precise formdisclosed above. Although specific embodiments of, and examples for, thetechnology are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the technologyas those of ordinary skill in the relevant art will recognize. Forexample, although steps are presented in a given order, alternativeembodiments may perform steps in a different order. The variousembodiments described herein may also be combined to provide furtherembodiments.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but well-known structures and functions have not been shown or describedin detail to avoid unnecessarily obscuring the description of theembodiments of the technology. Where the context permits, singular orplural terms may also include the plural or singular term, respectively.Moreover, unless the word “or” is expressly limited to mean only asingle item exclusive from the other items in reference to a list of twoor more items, then the use of “or” in such a list is to be interpretedas including (a) any single item in the list, (b) all of the items inthe list, or (c) any combination of the items in the list. For example,as used herein, including in the claims, “or” as used in a list of items(for example, a list of items prefaced by a phrase such as “at least oneof” or “one or more of”) indicates an inclusive list such that, forexample, a list of at least one of A, B, or C means A or B or C or AB orAC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase“based on” shall not be construed as a reference to a closed set ofconditions. For example, an exemplary step that is described as “basedon condition A” may be based on both a condition A and a condition Bwithout departing from the scope of the present disclosure. In otherwords, as used herein, the phrase “based on” shall be construed in thesame manner as the phrase “based at least in part on.” Additionally, theterms “comprising,” “including,” “having,” and “with” are usedthroughout to mean including at least the recited feature(s) such thatany greater number of the same feature and/or additional types of otherfeatures are not precluded.

The processing device (e.g., processor 130 and/or another controller)represents one or more general-purpose processing devices such as amicroprocessor, a central processing circuit, or the like. Moreparticularly, the processing device can be complex instruction setcomputing (CISC) microprocessor, reduced instruction set computing(RISC) microprocessor, very long instruction word (VLIW) microprocessor,or processor implementing other instruction sets, or processorsimplementing a combination of instruction sets. Processing device (e.g.,processor 130 and/or another controller) can also be one or morespecial-purpose processing devices such as an application specificintegrated circuit (ASIC), a field programmable gate array (FPGA), adigital signal processor (DSP), network processor, or the like.

The machine-readable storage medium (also known as a computer-readablemedium) on which is stored one or more sets of instructions or softwareembodying any one or more of the methodologies or functions describedherein. The machine-readable storage medium can be, for example, memorysystem 100 or another memory device. The term “machine-readable storagemedium” should be taken to include a single medium or multiple mediathat store the one or more sets of instructions. The term“machine-readable storage medium” shall also be taken to include anymedium that is capable of storing or encoding a set of instructions forexecution by the machine and that cause the machine to perform any oneor more of the methodologies of the present disclosure. The term“machine-readable storage medium” shall accordingly be taken to include,but not be limited to, solid-state memories, optical media and magneticmedia.

It will also be appreciated that various modifications may be madewithout deviating from the disclosure. For example, one of ordinaryskill in the art will understand that various components of thetechnology can be further divided into subcomponents, or that variouscomponents and functions of the technology may be combined andintegrated. In addition, certain aspects of the technology described inthe context of particular embodiments may also be combined or eliminatedin other embodiments. Furthermore, although advantages associated withcertain embodiments of the new technology have been described in thecontext of those embodiments, other embodiments may also exhibit suchadvantages and not all embodiments need necessarily exhibit suchadvantages to fall within the scope of the technology. Accordingly, thedisclosure and associated technology can encompass other embodiments notexpressly shown or described.

I/We claim:
 1. An apparatus, comprising: an array of memory cells; aplurality of bit-lines, each bit-line connected to a respective set ofmemory cells of the array of memory cells; and a memory subsystem havinga set of first memory circuits and a set of second memory circuits, eachfirst memory circuit disposed laterally adjacent to a second memorycircuit, each first memory circuit including a first bit-line connectionand each second memory circuit including a second bit-line connection,the first and second bit-line connections adapted to connect torespective bit-lines of the plurality of bit-lines, wherein each of thefirst bit-line connections is disposed on a first bit-line connectionline of the memory subsystem and each of the second bit-line connectionsis disposed on a second bit-line connection line of the memorysubsystem, wherein the second bit-line connection line is offset fromthe first bit-line connection line by a predetermined distance that isgreater than zero, wherein a first bit-line pitch is defined by adistance between the first bit-line connection and the second bit-lineconnection, and wherein, for a same effective distance between adjacentfirst and second bit-line connections, the first bit-line pitch is lessthan a second bit-line pitch that is defined by a distance betweenadjacent bit-line connections on a same bit-line connection line.
 2. Theapparatus of claim 1, wherein the memory subsystem is a voltageisolation device and the first and second memory circuits isolate highvoltage on the first and second bit-lines from low voltage circuitsconnected to the memory subsystem.
 3. The apparatus of claim 2, whereineach first memory circuit includes a first low-voltage connection thatis configured to connect to the low-voltage circuits, the first bit-lineconnection and a first data gate configured to selectively connect thefirst bit-line connection to the first low-voltage connection, and eachsecond memory circuit includes a second low-voltage connection that isconfigured to connect to the low-voltage circuits, the second bit-lineconnection and a second data gate configured to selectively connect thesecond bit-line connection to the second low-voltage connection.
 4. Theapparatus of claim 1, wherein the memory subsystem is configured suchthat the first and second memory circuits are mirrored along acenterline of the memory subsystem so as to form opposing pairs of firstmemory circuits across the centerline and opposing pairs of secondmemory circuits across the centerline.
 5. The apparatus of claim 4,wherein the memory subsystem is configured to have a common gate alongthe centerline to connect the first and second bit-line connections,wherein the common gate includes at least one opening for a sourceconnection, and wherein the at least one opening for a source connectionis disposed between the opposing pairs of first memory circuits.
 6. Theapparatus of claim 5, wherein in the common gate includes well implantlayers that are disposed perpendicular to at least one of a linecorresponding to the effective distance between the adjacent first andsecond bit-line connections or a line corresponding to a secondeffective distance between the source connection and the second bit-lineconnection.
 7. The apparatus of claim 6, wherein the at least one of thesource connections and an adjacent opening for the second bit-lineconnection includes facets along the line corresponding to the secondeffective distance.
 8. The apparatus of claim 1, wherein the memorysubsystem is configured to have at least two shared gates along acenterline of the memory subsystem, the at least two gates separated bya continuous source implant area, each shared gate configured to connectrespective first and second bit-line connections, and wherein thecontinuous source implant area includes at least one source connection.9. The apparatus of claim 8, wherein the at least two gates includes afirst gate and a second gate, and wherein the memory subsystem isconfigured such that the first and second memory circuits on a side ofthe first gate are offset with the first and second memory circuits on aside of the second gate, and wherein the circuit offset is such that thefirst memory circuits on the first gate side align with second memorycircuit on the second gate side and the second memory circuits on thefirst gate side align with first memory circuit on the second gate side,and wherein a source connection of the at least one source connection isdisposed in the continuous source implant area between each pair ofopposing first and second memory circuits.
 10. The apparatus of claim 1,wherein the first bit-line pitch is less than a minimum effectivedistance for the memory subsystem.
 11. An apparatus, comprising: a setof first protection circuits, each first protection circuit having afirst voltage connection; and a set of second protection circuits, eachsecond protection circuit having a second voltage connection, whereineach first protection circuit disposed adjacent to a second memorycircuit in a first direction, wherein each second voltage connection isoffset from an adjacent first voltage connection in a second directionthat is perpendicular to the first direction, the offset being apredetermined distance that is greater than zero, wherein a first pitchis defined by a distance between the first voltage connection and theadjacent second voltage connection in the first direction, and wherein,for a same effective distance between the second voltage connection andthe adjacent first voltage connection, the first pitch is less than asecond pitch that is defined by a distance between adjacent first andsecond voltage connections that are not offset in the second direction.12. The apparatus of claim 11, wherein the first and second protectioncircuits are voltage isolation devices that isolate high voltage onbit-lines of a memory subsystem connected to the respective first andsecond voltage connections from low voltage circuits of the memorysubsystem.
 13. The apparatus of claim 11, wherein an arrangement of thefirst and second protection circuits is such that the first and secondprotection circuits are mirrored along a centerline of the arrangementso as to form opposing pairs of first protection circuits across thecenterline and opposing pairs of second protection circuits across thecenterline.
 14. The apparatus of claim 13, wherein a common gate isdisposed along the centerline to connect the first and second voltageconnections, wherein the common gate includes at least one opening for asource connection, and wherein the at least one opening for a sourceconnection is disposed between the opposing pairs of first protectioncircuits.
 15. The apparatus of claim 14, wherein the common gateincludes well implant layers that are disposed perpendicular to at leastone of a line corresponding to the effective distance between theadjacent first and second source connections or a line corresponding toa second effective distance between the source connection and the secondvoltage connection.
 16. The apparatus of claim 11, wherein anarrangement of the first and second protection circuits is such that atleast two shared gates are disposed along a centerline of thearrangement, the at least two gates separated by a continuous sourceimplant area, each shared gate configured to connect respective firstand second voltage connections, and wherein the continuous sourceimplant area includes at least one source connection.
 17. The apparatusof claim 16, wherein the at least two gates includes a first gate and asecond gate, and wherein the first and second protection circuits on aside of the first gate are offset with the first and second protectioncircuits on a side of the second gate, and wherein the circuit offset issuch that the first protection circuits on the first gate side alignwith second protection circuit on the second gate side and the secondprotection circuits on the first gate side align with first protectioncircuit on the second gate side, and wherein a source connection of theat least one source connection is disposed in the continuous sourceimplant area between each pair of opposing first and second memorycircuits.
 18. The apparatus of claim 11, wherein each first protectioncircuit includes a third voltage connection that is configured toconnect to low-voltage circuits, the first voltage connection and afirst data gate configured to selectively connect the first voltageconnection to the third voltage connection, and wherein each secondprotection circuit includes a fourth voltage connection that isconfigured to connect to the low-voltage circuits, the second voltageconnection and a second data gate configured to selectively connect thesecond voltage connection to the fourth voltage connection.
 19. Theapparatus of claim 18, wherein an edge of the second data gate adjacentthe second voltage connection is not staggered in the second directionwith respect to an edge of the first data gate adjacent the firstvoltage connection.
 20. The apparatus of claim 18, wherein an edge ofthe second data gate adjacent the second voltage connection is staggeredin the second direction with respect to an edge of the first data gateadjacent the first voltage connection.